As described in GB No. 2106935A corresponding to Japanese Patent Application (OPI) No. 1420/84 it is known that GRA is a component of the membrane of a cancer cell, which can bind a lectin capable of binding a terminal galactose and/or terminal N-acetyl galactosamine, acts as an immunogen for the host and has very high immunogenicity that causes an immune response specific to the cancer cells and that this exhibits an excellent effect in the therapy and prophylaxis of cancer.